Full-size-fraction coal gasification slag in-situ carbon ash and water synergistic efficient separation method

Abstract

The invention discloses a full-size-fraction coal gasification slag in-situ carbon ash water synergistic efficient separation method, which belongs to the technical field of coal chemical industry, and comprises the following steps: converting gasification fine slag and gasification coarse slag to form gasification ash water; sorting the gasified ash water to obtain high-carbon slag and high-ash slag; filtering and dehydrating the high-carbon slag and the high-ash slag; and dehydrating the dehydrated high-carbon residues and high-ash residues by adopting a high-speed rotational flow low-temperature activation method to obtain the high-carbon residues with the water content of less than 33% and the high-ash residues with the water content of less than 8%. The method is adopted at the tail end of the gasification process, and efficient in-situ carbon ash water separation of the whole-size-fraction coal gasification slag is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of coal chemical industry, and in particular to a method for the efficient synergistic separation of in-situ carbon, ash and water from full-size coal gasification slag. Background Art

[0002] Coal gasification is a key reaction process in the coal chemical industry, but it inevitably produces a byproduct called gasification slag. During coal chemical production, entrained-flow gasification (e.g., water-coal slurry gasification, dry coal pulverization gasification), produces a large amount of highly water-rich gasification slag. This slag typically contains over 20% fixed carbon, making it a fuel. However, its high moisture content and high viscosity restrict its resource utilization.

[0003] The existing methods for treating coal gasification slag black water have the following problems:

[0004] (1) The moisture content of the filter cake obtained by vacuum filtration and mechanical pressure filtration of the existing coal gasification slag black water is still higher than 40%. Although the high-temperature drying process can deeply dehydrate it, the energy consumption is too high;

[0005] (2) Existing separation technologies fail to synergistically separate and dispose of gasification coarse slag and fine slag based on their different properties;

[0006] (3) Most of the gasification slag is directly landfilled and cannot be effectively utilized. Summary of the Invention

[0007] The object of the present invention is to provide a method for the efficient synergistic separation of in-situ carbon, ash and water from full-size coal gasification slag, so as to solve the technical problems mentioned in the background technology.

[0008] To achieve the above object, the present invention provides a method for the efficient synergistic separation of in-situ carbon, ash and water from full-size coal gasification slag, comprising the following steps:

[0009] S1. The gasification fine slag and gasification coarse slag discharged from the gasifier are converted into gasification ash water, which enters the water medium gravity cyclone separator through a pipeline;

[0010] S2. Using a water-medium gravity cyclone separator, the gasified ash water obtained in step S1 is separated to obtain high-carbon slag and high-ash slag, which are then fed into a vacuum filter through a pipeline;

[0011] S3, using a vacuum filter to filter the high carbon slag and high ash slag obtained in step S2, and the filtered high carbon slag and high ash slag enter the cyclone dryer through a pipeline;

[0012] S4, a cyclone dryer uses a high-speed cyclone low-temperature activation method to dehydrate the high carbon slag and high ash slag obtained in step S3 to obtain high carbon slag with a moisture content of less than 33% and high ash slag with a moisture content of less than 8%.

[0013] Preferably, in step S1, the particle size of the gasified fine slag is 10-200 microns, and the particle size of the gasified coarse slag is 200-3000 microns.

[0014] Preferably, in step S2, a water-medium gravity cyclone separator is used to separate the gasification ash water to obtain high carbon slag with a water content higher than 90% and high ash slag with a water content higher than 90%.

[0015] Preferably, in step S3, high carbon slag and high ash slag are filtered and dehydrated by vacuum filtration dehydration to obtain high carbon slag with a water content of 50-55% and high ash slag with a water content of 15-20%.

[0016] Preferably, the high-speed cyclone low-temperature activation method in step S4 is: a high-speed airflow is provided to the cyclone dryer by a fan, and the airflow temperature of the cyclone dryer is controlled by a temperature controller.

[0017] Preferably, the air flow velocity in the high-speed cyclone low-temperature activation method is 35-50 m / s.

[0018] Preferably, the air flow temperature in the high-speed cyclone low-temperature activation method is 50-70°C.

[0019] Preferably, the air flow temperature comes from the 50-70° C. waste heat carried by the gasified ash water itself and the low-pressure steam heat recovery.

[0020] Therefore, the present invention adopts the above-mentioned method for the efficient synergistic separation of in-situ carbon, ash and water from full-size coal gasification slag, which has the following beneficial effects:

[0021] (1) By in-situ sorting of coal gasification slag of all particle sizes, the complementarity of coarse and fine slag is fully utilized to improve sorting efficiency;

[0022] (2) After separation, the properties of high carbon slag and high ash slag change. The separation process breaks the strong water holding characteristics of the original gasification slag. After filtering and dehydrating them separately, the average moisture content of the filter cake is 15-20% lower than that of the original slag.

[0023] (3) High-speed cyclone low-temperature activation technology is used to further dehydrate the high-moisture filter cake obtained by vacuum filtration or mechanical filter pressing. The fan of the high-speed cyclone low-temperature activation technology provides high-speed airflow, and the temperature controller controls the temperature rise of the airflow. The high-speed cyclone process generates shear force, centrifugal force, drag force and micro-vibration of the particle interface, so that the moisture between the high-moisture filter cake particles and the moisture inside the pores on the particle surface are quickly separated from the solid particles. This process does not involve the loss of latent heat of vaporization caused by high-temperature drying, and has the advantages of low-temperature, normal pressure, continuous and low-energy dehydration.

[0024] (4) Through efficient separation of carbon ash and water, three usable components are directly obtained, realizing resource utilization and avoiding pollution, disposal costs and waste of resources caused by the transportation and landfill process.

[0025] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Flowchart of a method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] Example

[0029] like Figure 1 As shown, a method for the efficient synergistic separation of in-situ carbon, ash and water from full-size coal gasification slag comprises the following steps:

[0030] S1. The entrained-flow coal gasification slag is divided into coarse slag discharged from the bottom of the gasifier and fine slag discharged together with the synthesis gas. The fine gasification slag (mainly with a particle size of 10-200 microns) and the coarse gasification slag (mainly with a particle size of 200-3000 microns) are both converted into gasification ash water, which enters the water medium gravity cyclone separator through a pipeline.

[0031] S2. Based on the differences in the characteristics of the particles in the in-situ ash water of the coarse slag and fine slag from coal gasification (such as size, density, etc.), the gasification ash water is sorted by water medium cyclone. Specifically: the high carbon slag and high ash slag obtained are filtered and dehydrated using a water medium gravity cyclone separator to obtain a gasification slag filter cake, and high carbon slag with a water content higher than 90% and high ash slag with a water content higher than 90% are obtained. The high carbon slag and high ash slag enter the vacuum filter through a pipeline. Among them, the carbon content of the high carbon slag is 70-78%; the carbon content of the high ash slag is 5-8%. In this step, the coarse slag drives the fine slag to intensify the sorting. Compared with foam flotation, water medium cyclone sorting does not involve the consumption of flotation reagents and has low energy consumption.

[0032] S3. Use a vacuum filter, i.e., vacuum filtration and dehydration method, to vacuum filter and dehydrate the high carbon slag and high ash slag to obtain high carbon slag with a water content of 50-55% and high ash slag with a water content of 15-20%. The gasified slag filter cake enters the cyclone dryer through a pipeline.

[0033] The S4 cyclone dryer uses a high-speed cyclone, low-temperature activation method to deeply dehydrate high-carbon slag with a moisture content of 50-55% and high-ash slag with a moisture content of 15-20%, producing high-carbon slag with a moisture content below 33% and high-ash slag with a moisture content below 8%. This high-speed cyclone, low-temperature activation method uses a fan to provide a high-speed airflow, while a temperature controller controls the airflow temperature. The airflow velocity is 35-50 m / s, and the airflow temperature is controlled at 50-70°C. This airflow temperature is derived from the heat recovery of low-pressure steam from the plant and the 50-70°C waste heat carried by the vaporized ash water. The thermal effect of the 50-70°C airflow prevents high energy consumption during the liquid-liquid separation process due to the latent heat of vaporization during phase change. The gentle temperature primarily reduces liquid viscosity and increases fluidity. The change in contact angle reduces capillary forces, reducing the capillary forces that restrict pore water, thereby enhancing the solid-liquid separation process.

[0034] All of the above steps are carried out in the factory. By combining a high-speed cyclone low-temperature activation device with a gasification process, the carbon, ash, and water in the gasification slag are separated in situ at the end of the gasification process. This achieves efficient in-situ separation of carbon, ash, and water in gasification slag of all particle sizes, rationally utilizing resources while reducing transportation, landfill costs, and environmental pollution.

[0035] In order to better illustrate the method of the present invention, an application example is used for illustration.

[0036] Example 1

[0037] S1. Converting gasification fine slag (main particle size 10-200 microns) and gasification coarse slag (main particle size 200-3000 microns) into gasification ash water, wherein the ratio of gasification coarse slag to gasification fine slag is 4:1.

[0038] S2. The gasified ash water is separated by a water medium cyclone separator to obtain high carbon slag with a water content of 93% and a carbon content of 78% and high ash slag with a water content of 92% and a carbon content of 5%.

[0039] S3. Use a vacuum filter to filter and dehydrate the high carbon slag and the high ash slag to obtain high carbon slag with a water content of 55% and high ash slag with a water content of 15%, respectively.

[0040] S4. The cyclone dryer uses a high-speed cyclone low-temperature activation method to deeply dehydrate the high-carbon slag with a moisture content of 55% to obtain a high-carbon slag with a moisture content of 30%, and to deeply dehydrate the high-ash slag with a moisture content of 15% to obtain a high-ash slag with a moisture content of 5%. The temperature is set at 70°C and the air flow velocity is 50m / s.

[0041] Example 2

[0042] S1. Converting gasification fine slag (mainly with a particle size of 10-200 microns) and gasification coarse slag (mainly with a particle size of 200-3000 microns) into gasification ash water, wherein the ratio of gasification fine slag to gasification coarse slag is 3:2.

[0043] S2. The gasified ash water is separated by a water medium cyclone separator to obtain high carbon slag with a water content of 92% and a carbon content of 72% and high ash slag with a water content of 92.5% and a carbon content of 6.2%.

[0044] S3. Use a vacuum filter to filter and dehydrate the high carbon slag and high ash slag to obtain high carbon slag with a water content of 53% and high ash slag with a water content of 17%, respectively.

[0045] S4. The cyclone dryer uses a high-speed cyclone low-temperature activation method to deeply dehydrate the high-carbon slag with a moisture content of 53% to obtain a high-carbon slag with a moisture content of 28%, and to deeply dehydrate the high-ash slag with a moisture content of 17% to obtain a high-ash slag with a moisture content of 7%. The temperature is set at 60°C and the air flow velocity is 45m / s.

[0046] Example 3

[0047] S1. Converting gasification fine slag (mainly with a particle size of 10-200 microns) and gasification coarse slag (mainly with a particle size of 200-3000 microns) into gasification ash water, wherein the ratio of gasification fine slag to gasification coarse slag is 2:3.

[0048] S2. The gasified ash water is separated by a water medium cyclone separator to obtain high carbon slag with a water content of 91% and a carbon content of 70% and high ash slag with a water content of 93% and a carbon content of 8%.

[0049] S3. Use a vacuum filter to filter and dehydrate the high carbon slag and the high ash slag to obtain high carbon slag with a water content of 51% and high ash slag with a water content of 20%, respectively.

[0050] S4. The cyclone dryer uses a high-speed cyclone low-temperature activation method to deeply dehydrate the high-carbon slag with a moisture content of 51% to obtain a high-carbon slag with a moisture content of 28%, and to deeply dehydrate the high-ash slag with a moisture content of 20% to obtain a high-ash slag with a moisture content of 8%. The temperature is set at 50°C and the air flow velocity is 35m / s.

[0051] Example 4

[0052] Compared with Example 1, the temperature was set to 50° C., and other conditions remained unchanged, to obtain high carbon slag with a moisture content of 33% and high ash slag with a moisture content of 6%.

[0053] Therefore, the present invention adopts the above-mentioned method for the coordinated and efficient separation of in-situ carbon, ash and water from full-size coal gasification slag, and adopts a water medium cyclone method to carry out in-situ carbon and ash separation of the gasification slag ash water from the coal gasification plant area through the difference in carbon and ash density and particle size. The gasification slag after sorting has a strong water holding capacity and is destroyed, and then the filtrate is recovered through vacuum filtration and high-speed cyclone dehydration, thereby realizing the efficient separation of in-situ carbon, ash and water from full-size coal gasification slag.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for the efficient synergistic separation of in-situ carbon, ash and water from full-size coal gasification slag, characterized in that the steps include: S1. The gasification fine slag and gasification coarse slag discharged from the gasifier are converted into gasification ash water, which enters the water medium gravity cyclone separator through a pipeline; S2. Using a water-medium gravity cyclone separator, the gasified ash water obtained in step S1 is separated to obtain high-carbon slag and high-ash slag, which are then fed into a vacuum filter through a pipeline; S3, using a vacuum filter to filter the high carbon slag and high ash slag obtained in step S2, and the filtered high carbon slag and high ash slag enter the cyclone dryer through a pipeline; S4, a cyclone dryer uses a high-speed cyclone low-temperature activation method to dehydrate the high carbon slag and high ash slag obtained in step S3 to obtain high carbon slag with a moisture content of less than 33% and high ash slag with a moisture content of less than 8%.

2. The method for the efficient synergistic separation of in-situ carbon, ash and water from full-size coal gasification slag according to claim 1, characterized in that: In step S1, the particle size of the gasified fine slag is 10-200 microns, and the particle size of the gasified coarse slag is 200-3000 microns.

3. The method for the efficient in-situ separation of carbon, ash and water from full-size coal gasification slag according to claim 1, characterized in that: In step S2, a water-medium gravity cyclone separator is used to separate the gasified ash water to obtain high-carbon slag with a water content higher than 90% and high-ash slag with a water content higher than 90%.

4. The method for the efficient in-situ separation of carbon, ash and water from full-size coal gasification slag according to claim 1, characterized in that: In step S3, the high carbon slag and the high ash slag are filtered and dehydrated by vacuum filtration dehydration to obtain high carbon slag with a water content of 50-55% and high ash slag with a water content of 15-20%.

5. The method for the efficient synergistic separation of in-situ carbon, ash and water from full-size coal gasification slag according to claim 1, characterized in that: The high-speed cyclone low-temperature activation method in step S4 is as follows: a high-speed airflow is provided to the cyclone dryer by a fan, and the airflow temperature of the cyclone dryer is controlled by a temperature controller.

6. The method for the efficient synergistic separation of in-situ carbon, ash and water from full-size coal gasification slag according to claim 5, characterized in that: The air flow velocity in the high-speed swirl low-temperature activation method is 35-50 m / s.

7. The method for the efficient in-situ separation of carbon, ash and water from full-size coal gasification slag according to claim 5, characterized in that: The air flow temperature in the high-speed cyclone low-temperature activation method is 50-70°C.

8. The method for the in-situ synergistic and efficient separation of carbon, ash and water from full-size coal gasification slag according to claim 7, characterized in that: The air flow temperature comes from the waste heat carried by the gasified ash water itself and the heat recovery of the factory's low-pressure steam.

Images